Research indicates that adopted children are more likely than peers in the general population to exhibit psychosocial and behavior problems. Disagreement persists about the validity of this finding and its interpretations, partly because the majority of studies about adopted children in the United States are based on small and/or non- representative samples. Using a large nationally representative sample, we will compare adopted and non-adopted adolescents on measures of school achievement; use of alcohol, tobacco, and illegal drugs; sexual behavior; internalizing and externalizing problems. Data will come from a 1994-1996 survey (Add Health) of about 90,000 adolescents between the ages of 12 and 17, and home interviews with approximately 20,000 adolescents and 18,000 of their parents. Analyses will go beyond descriptive comparisons to statistically control for other variables that differentiate adoptive from biological families. Further, based primarily on psychosocial theories of human development and stress and coping, mediating mechanisms will be investigated that could explain the often reported differences in psychosocial well being and behavior problems for adopted and non-adopted adolescents. Structure equation models will test how individual and family processes mediate psychosocial and behavior outcomes. The proposed analyses will provide more conclusive evidence to help resolve several important controversies about the consequences of adoption. Because approximately 100,000 domestic adoptions occur each year in the United States it is important o know the extent to which adopted children are at risk. More importantly, we will identify characteristics of adopted children and their families for whom interventions would be most beneficial, and suggest variables that could provide a focus for interventions.